Antiplatelet Resumption after Antiplatelet-Related Intracerebral Hemorrhage: A Retrospective Hospital-Based Study.

BACKGROUND: Antiplatelet resumption in patients who developed intracerebral hemorrhage (ICH) while on antiplatelet therapy (antiplatelet-related ICH) represents an important medical dilemma. We aimed to study the long-term cardiovascular outcomes of antiplatelet-related ICH survivors, and the risk of recurrent ICH with antiplatelet resumption. METHODS: This was an observational study of 109 antiplatelet-related ICH survivors. The clinical end points were recurrent ICH, ischemic vascular events, and vascular death (fatal ICH or ischemic vascular events). Predictors of recurrent ICH and vascular death were derived using a multivariable Cox regression model. RESULTS: The median duration of follow-up was 3.5 years (interquartile range, 1.6-5.8 years). Ischemic vascular events were more common than recurrent ICHs (6.8 per 100 patient-years vs. 2.6 per 100 patient-years; P = 0.028). Antiplatelet use was not associated with an elevated risk of recurrent ICH (hazard ratio [HR], 1.11, 95% confidence interval [CI], 0.27-4.62). A mean follow-up systolic blood pressure of >140 mmHg increased the risk of both recurrent ICH (HR, 4.28; 95% CI, 1.01-18.11) and vascular death (HR, 11.14; 95% CI, 2.72-45.62). Cerebral amyloid angiopathy (CAA) was an independent predictor for recurrent ICH (HR, 24.34; 95% CI, 2.80-211.47). CONCLUSIONS: Antiplatelet resumption after antiplatelet-related ICH did not appear to carry a clinically significant risk of recurrent ICH, whereas inadequate blood pressure control and CAA contributed to a more robust risk. Antiplatelet resumption should be considered, especially in survivors with adequate blood pressure control and without CAA.

Reactive component selection for TET powered medical devices.

Transcutaneous energy transfer (TET) is capable of supplying power across the skin to implantable devices and avoids the risk of infection associated with wires passing through the skin. These systems rely on a high frequency magnetic field to overcome the relatively low coupling between a coil located outside the body, and a coil implanted within the body. This paper introduces a new optimisation procedure to choose tuning capacitors that minimises the amount of power dissipated in the power transfer coils of an implantable TET system. The frequency of operation is determined by the selection of the resonant reactive components. By analysing the overall circuit impedance it is possible to observe that a Zero Voltage Switched TET system may dissipate different amounts of power in the power transfer coils while delivering the same amount of power. In this study an objective function was developed to determine the best configuration of resonant capacitors for any particular set of TET coils in order to minimize power loss. The method is used to find the value of the resonant capacitors for a system delivering 15 W over a coupling range of k=0.1 to 0.55 (corresponding to a separation of up to 20mm).